Two-dimensional multi-beam stabilizer and combining systems and methods

ABSTRACT

A system and method for stabilizing and combining multiple emitted beams into a single system using both WBC and WDM techniques.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/766,923, filed Feb. 14, 2013, which claims the benefit of andpriority to U.S. Provisional Patent Application No. 61/598,470, filed onFeb. 14, 2012, the entire disclosure of each of which is herebyincorporated herein by reference.

COPYRIGHT INFORMATION

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present embodiments relate generally to laser systems and moreparticularly to wavelength beam combining systems and methods.

2. Description of the Prior Art

Wavelength beam combining (WBC) and Wavelength-division multiplexing(WDM) systems have been developed to scale up power for a single outputbeam (comprised of a plurality of wavelengths) to be used in a varietyof applications. However, the optical architecture of previous highpower systems often requires certain optical elements in those WBC orWDM systems to withstand high amounts of thermal loading, which leads toexpensive and high cost systems. What is needed are alternative systemsthat divert thermal loading and allow for lower cost components to beused, as well as enable simpler manufacturing and set up.

The present systems and methodologies described herein seek to combineWDM and WBC techniques into a common system achieve lower thermalloading, allow for lower tolerance components and be more flexiblescalable high power and brightness systems.

The following application seeks to solve the problems stated.

SUMMARY OF THE INVENTION

A system for stabilizing and combining multiple beams to be emitted as ahigh brightness multi-wavelength beam comprising a stabilizer/resonatorsystem in conjunction with a beam combiner system.

In one embodiment, a transform lens and other optical elements areshared between each system.

In one embodiment, a diffraction grating is utilized by both systems.

In one embodiment, 0^(th) order feedback is used to wavelength stabilizethe emitters in the resonator/stabilizer portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a Littrow resonator.

FIGS. 2A and 2B illustrate a schematic of a wavelength resonator andwavelength combiner system.

FIGS. 3A and 3B illustrate an embodiment of a wavelength stabilizercavity.

FIGS. 4A and 4B illustrate an embodiment of a wavelength combiner.

FIGS. 5A and 5B illustrate an embodiment of a wavelength stabilizercavity.

FIGS. 6A and 6B illustrate an embodiment of a wavelength combiner.

FIG. 7 illustrates a Littman-Metcalf external-cavity system.

FIGS. 8A and 8B illustrate an embodiment of a wavelength stabilizercavity using a reflective surface.

FIGS. 9A and 9B illustrate another embodiment of a wavelength stabilizercavity using a reflective surface.

FIGS. 10A and 10B illustrate an embodiment of a wavelength combiner.

FIGS. 11A and 11B illustrate an embodiment of a wavelength stabilizercavity emitting stabilized beams out of the back facet of an opticalgain medium.

FIGS. 12A and 12B illustrate an embodiment of a wavelength stabilizercavity emitting stabilized beams using a polarized cube.

FIGS. 13A and 13B illustrate a hybrid wavelength stabilizer/combinercavity embodiment where optical elements are shared.

FIG. 14 illustrates another hybrid wavelength stabilizer/combiner cavityembodiment where the dispersive element is shared.

FIG. 15 illustrates a conventional WBC cavity where the output coupleris placed on the 1st order of the diffraction grating.

FIG. 16 illustrates a hybrid WBC system using 0^(th) order feedback tostabilize the emitters.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Aspects and embodiments relate generally to the field of scaling lasersources to high-power and high-brightness using wavelength beamcombining techniques. More particularly, methods for increasingbrightness, stability, and effectiveness of wavelength beam combiningsystems.

Embodiments described herein include addressing: 1) increasing outputpower and brightness through combining multiple emitters in a commonsystem incorporating WDM and WBC techniques. Through the variousembodiments and techniques described herein a stabilized, highbrightness multi-wavelength output laser system may be achieved.

The approaches and embodiments described herein may apply to one andtwo-dimensional beam combining systems along the slow-axis, fast-axis,or other beam combining dimension. For purposes of this applicationoptical elements may refer to any of lenses, mirrors, prisms and thelike which redirect, reflect, bend, or in any other manner opticallymanipulate electromagnetic radiation. Additionally, the term beamincludes electromagnetic radiation. Beam emitters include anyelectromagnetic beam-generating device such as semiconductor elements,which generate an electromagnetic beam, but may or may not beself-resonating. These also include fiber lasers, disk lasers, non-solidstate lasers, diode lasers and so forth. Generally each emitter iscomprised of a back reflective surface, at least one optical gainmedium, and a front reflective surface. The optical gain medium refersto increasing the gain of electromagnetic radiation and is not limitedto the visual, IR or ultraviolet portions of the electromagneticspectrum. An emitter, may be comprised of multiple beam emitters such asa diode bar configured to emit multiple beams.

Wavelength beam combining is a proven method for scaling the outputpower and brightness from diode elements. Here we disclose a new methodfor side-by-side spatial and wavelength beam combining in a commonsystem. The central concept consists of a single-resonatormulti-wavelength stabilizer and a separate wavelength combiner fortwo-dimensional diode elements. One goal and outcome of the embodimentsdescribed herein is to create a plurality of unique wavelengths that arestabilized and resonating in a multi-cavity system configured to becombined or overlapped into a common beam profile.

Wavelength Stabilizing/Wavelength Combining

There are several methods for wavelength stabilizing diode elements.FIG. 1 shows a well-known Littrow resonator 100 for stabilizing a singleradiation emitter 102 into a narrowed and well defined wavelength 105.Typically the optical architecture 100 consists of a transform optic orcollimation optics 108 and a diffraction grating 114. The transformoptics 108 collimates the emission 103 from the single emitter 102, suchas a diode element. Usually the emitted beam, after the transformoptics, has a very long Raleigh range, so placement of the diffractiongrating 114 is less critical. The first order produced from the grating114 by diffracting the emitted beam 103 is used as feedback 110. Aresonator is formed between the back facet of the single emitter 102(diode element) and the diffraction grating 114.

As mentioned, one purpose of this application is to provide amulti-wavelength stabilizer and a separate wavelength combiner fortwo-dimensional diode elements. FIGS. 2A-B help illustrate this centralconcept. The left sides of FIGS. 2A-B show a multi-wavelength stabilizerresonator 210 a-b. The right sides of FIGS. 2A-B show a wavelengthcombiner 220 a-b. Generally fundamental to any wavelength stabilizationresonator and wavelength combiner is a dispersive element. For purposesof this disclosure we assume that dispersion occurs along one opticalaxis only, unless otherwise specified. Along the dispersion dimension(FIG. 2A) the main function of the multi-wavelength stabilizer resonator210 a is to stabilize each emitter 202 (such as an optical gain elementor other radiation producing element described above) along thisdispersion dimension to produce a unique and well-defined or distinctwavelength(s) output 205 a having a narrow bandwidth. A stabilizer 204may include a dispersive element and optical elements configured to takethe emitted beams 203 a and return at least a portion of those beamsinto the emitters 202 having well-defined or unique wavelengths that aregenerally narrow in bandwidth.

Along the non-dispersion dimension, (FIG. 2B) the main function of theresonator 210 b is to form a resonator for each of the diode or otheroptical gain elements 202. The main function of the wavelength combiner220 a-b is to take the two-dimensional beams from the stabilizerresonator 210 a-b and generate a one-dimensional beam. Along thedispersion axis 200 a the combiner 222 takes multiple input beams 205 aand overlaps and/or combines each into a single beam profile 225 a. Thesingle profile is comprised of a plurality of unique wavelengthsoverlapped along at least one dimension. The stabilized uniquewavelengths allow for this single profile to be formed while maintaininghigh brightness levels. Along the non-dispersion axis 200 b the opticalelements 224, such as telecentric optics, receive input beams 205 b andgenerate the same output beams 225 b with little or no degradation inoutput beam quality. In summary, two systems are combined to manageunique wavelength stabilization and efficient beam combination toproduce a high brightness and high output power multi-beam profile.

Wavelength Stabilizing Cavities

FIGS. 3A and 3B show one embodiment for generatingmulti-wavelength-stabilized elements using a variation of the Littrowresonator. The embodiment uses a chirped grating 314. In bothdimensions, a single telecentric optic system 306 is used. As shown, inits simplest form, the telecentric optics 306 used comprise of atwo-lens con-focal setup. The chirped grating 314 may be a surfacegrating or volume grating. In this embodiment it is only chirped alongone dimension, 300 a. In both the dispersive dimension 300 a andnon-dispersive dimension 300 b, the emitters 302 have the same incidenceangle onto the grating 314. The diffracted beams 308 a-b, from eachemitter is used as feedback to form a stable resonator. Since thegrating 314 is chirped each emitter is stabilized to a unique anddefined wavelength by the resonator formed between the chirped grating314 and back reflective facet of each emitter (not labeled). The outputbeam 305 a is taken from the zero order of the grating 314. Theembodiment disclosed in FIGS. 3A and 3B and other embodiments describebelow may include a multi-cavity system wherein multiple resonatingcavities are created. These resonating cavities may include a back facetreflector formed on one end of a radiation element or emitter and anycombination of or individual effective reflectivity of the front facet(not shown), dispersive element (or diffraction grating), partially orfully reflective mirror, and/or any other reflective optical elementused in the system. Some of these reflective optical elements, such asthe chirped grating shown in FIGS. 3A and 3B, act as a common reflectorto multiple emitters, wherein a common system is created. This commonsystem is one where multiple resonating cavities are created using thesame reflective optical element in part to create their respectivecavities. Thus, stabilizing each of the beams emitted by a plurality ofemitters. The output 305 a-b of the wavelength stabilizing system shownin FIGS. 3A and 3B may be the input to the wavelength beam combiner inFIGS. 4A and 4B.

FIGS. 5A and 5B illustrate the dispersive and non-dispersivearchitecture of another wavelength stabilizing using a variation of aLittrow resonator for stabilizing the 2-D emitters to desiredwavelengths using a constant groove density grating 514. Here along thedispersion dimension 500 a a transform optic 508 is used. The mainfunction of the transform optic(s) 508 is to convert unique near fieldpositions of the diode emitters 502 into unique angles onto the densitygrating 514. Feedback 510 a-b from grating 514 is redirected back intoelements 502 where a resonator system is formed with each of the emittedbeams having a unique wavelength. FIG. 5B shows the cavity along the nondispersion dimension 500 b. Here only telecentric optics 506 are usedalong the non-dispersion direction to ensure feedback 510 b isredirected into each of the emitters of 502, thus stabilizing resonancealong this dimension. The telecentric optics 506 as shown are comprisedof two cylindrical lenses. The output beam 505 a-b is a result of thezero order dispersion of grating 514. The output 505 a-b may used asinput for the wavelength combiner in FIGS. 6A and 6B.

FIG. 7 shows a conventional Littman-Metcalf external-cavity system 700for a single gain element/emitter 702. System 700 consists of a singleoptical gain element 702, collimation or transforms optics 708, adispersive element 714, and a totally reflective surface/mirror 730positioned to receive one of the diffracted orders of 714. A resonatoris formed between the back facet of the diode element 702 and the mirror730 as feedback 710 is redirected by the mirror 730 back to thediffraction grating 714, through 708 into the diode element 702. Theoutput beam 725 here is provided from the zero order of the dispersivegrating 714.

FIGS. 8A-B illustrate a method for stabilizing two-dimensional (2-D)elements 802 to the desired wavelengths incorporating a reflectivesurface 830. This variation of Littman-Metcalf cavity 700 is configuredfor use with 2-D emitters. Along the dispersion axis 800 a each diodeemitter 802 has a unique angle of incidence. Transform optical element808, having power in the dispersive dimension, but not in thenon-dispersive dimension, is used in part to help create these uniqueangles of incidence for each of the emitted beams 803 a. The first orderof diffracted beams from diffraction grating 814 propagates to themirror 830. A resonator is formed between the back facet (not labeled)of each of the diode emitters 802 and the mirror 830 by feedback 810a-b. As such each emitter along the dispersion axis is stabilized toprovide a unique and well-defined wavelength. Along the non-dispersionaxis 800 b a telecentric optic 806, having focal power only in thisdimension, is used to redirect feedback 810 b into emitters 802 andestablish resonance along this dimension. The telecentric-optic(s) 806optically transfers the beam waist of each emitter and projects it ontothe mirror, wherein the mirror acts as common reflector for the emittersto create multiple resonating cavities. The output beam is taken fromthe zero order of the grating. In this configuration all the optics(806,808) are cylindrical lenses. It should be noted that differentorders of light may be used for feedback in the various embodimentsdescribed herein, as well as output and are within the scope of thisapplication.

FIGS. 9A and 9B illustrate another method for stabilizing 2-D elements902 to the desired wavelengths incorporating a reflective surface 930.However, in this embodiment telecentric optic 906 is placed betweengrating 914 and mirror 930. 906 only has power in the non-dispersivedimension 900 b, but can be used in conjunction with transform optic908, here having power in both dimensions (900 a-b) to form atelescoping system for stabilizing the emitted beams 903 b and feedback910 b to form a resonant system along the non-dispersive dimension 900b. Transform optic 908 may be a spherical lens that causes beams 903 ato converge along the dispersive dimension 900 a onto diffractiongrating 914. Again feedback 910 a provide wavelength stabilized feedbackalong this dimension between the back facet of emitters 902 and mirror930. The output 905 a-b of FIGS. 9A and 9B and 805 a-b may be used asinput for the combiner of FIGS. 10A and 10B.

The previous output beams, from the above wavelength stabilizedconfigurations, are generally taken from the zero order of thedispersive component or grating. The output beam can also be takenintra-cavity (FIGS. 12A-B) or from another facet (FIGS. 11A-B).

FIGS. 11A-B illustrate an embodiment of a wavelength stabilizer cavityemitting stabilized beams where the output beam is taken or emitted fromthe back facet 1140. Emitted beams 1103 pass through telecentric optics1106 onto chirped grating 1114 where they are dispersed into orders andfeedback 1110 a-b is passed back towards emitters 1102 forming astabilized system. The output beams 1125 a-b are then emitted from theback facet 1140 of emitters 1102. Telecentric optics 1106 have power inboth the dispersive 1100 a and non-dispersive 1100 b dimensions. Output1125 a-b may then be used in conjunction with a wavelength combinersystem.

FIGS. 12A and 12B illustrate a configuration where the output beams 1225a and 1227 a are taken directly within the cavity. The preferred choicedepends on many parameters, one of which is the efficiency of thegrating 1214. For example, it may be preferred to take the output beamsfrom the zero order of the grating if the efficiency of the grating islow. Preferably the effective feedback 1210 a-b from chirped grating1214 is comparable to the reflectivity of the diode facet(s) of emitters1202 when optimized for output power. The configuration as shown inFIGS. 11A and 11B may be preferred for very robust wavelength lockingwhere the grating needs to be optimized to efficiently operate. The maindifference with the configuration in FIGS. 11A and 11B is the need tohave both facets of the diode emitters accessible. Intra-cavityextraction as shown in FIGS. 12A and 12B, may be a preferred method formultiple output beams. Output 1227 a may be an order that has littlelight or power in it and in some embodiments is redirected to a beamdump. In other embodiments a recycling system using reflective surfacesand/or additional optical elements to redirect and the output beams isalso contemplated. Output 1225 a comes by way of using a polarizing orbeam splitter optical element, such as a polarizing cube, to send amajority of the light out of the system while passing a smallerpercentage onto chirped grating 1214 to disperse the light into uniquewavelengths and send the stabilizing feedback into emitter 1202.

Wavelength Combiners

FIGS. 4A and 4B show a wavelength and spatial beam combiner configuredto receive the output 305 a-b from the wavelength stabilizerconfiguration shown in FIGS. 3A-B. Along the dispersion dimension 400 a,transform optic(s) 406 and grating 414 combine the output/input 305 ainto a single beam as illustrated in FIG. 4A. Along the non-dispersionaxis 400 b (FIG. 4B) telecentric optics 406 comprised of cylindricaloptics help reproduce the same incidence angle as the resonator fromFIGS. 3A and 3B. As such, ideally, the optics will preserve the qualityof input beam 305 b. Any deviations from this generally result indegradation of beam quality. These deviations include non-ideal matchingof transform optics and grating combination, position of grating atother places/positions besides where the chief rays are overlapped, andnon-telecentric optics along the non-dispersion axis. It should be notedin this configuration transform optic(s) 408 have power along thedispersion 400 a dimension to direct 305 a to converge towards 414.Telecentric optics 406 similarly only have power in the non-dispersiondimension 400 b. Output 425 is then comprised of a combined multiplewavelength beam 425 a along the dispersion dimension 400 a while theoutput 425 b along the non-dispersion dimension maintains the originalarray or number of emission beams from a 2-D profile.

FIGS. 6A and 6B show a beam combiner configured to receive the output505 a-b from the wavelength stabilizer configuration shown in FIGS. 5Aand 5B. The optical elements along the dispersion dimension/axis 600 ainclude a collimator 608 a, transform optic 608 b and grating 614. Thecollimator 608 a is configured to collimate the chief rays from input505 a and used with transform optic 608 b to converge or overlap thebeams onto grating 614. The combination of the two optical elements andgrating can be chosen to match the wavelength bandwidth of the diodeelements. Along the non-dispersion dimension 600 b all of the chief raysare parallel. A cylindrical telescope 606 comprised of cylindricaloptics again help reproduce the same incidence angle as the resonatorfrom FIGS. 5A and 5B and preserve the quality of input beam 505 b. Asshown in FIGS. 6A and 6B, there are four cylindrical lenses (606 a-b,608). Some of these lenses may be combined into a single spherical lenssuch that it performs the same functions as just described. For example,two spherical lenses may replace the 4 cylindrical lenses wherein theoutput beam 625 a-b would still be the same.

FIGS. 10A and 10B show a spatial and wavelength combiner implementationfor use with the resonator configurations shown in FIGS. 8A-9B. Alongthe dispersion axis 1000 a the optical elements consist of a chief raycollimator 1004 and a transform optic 1008. The collimator takes theoverlapped chief rays from input (805 a, 905 a) at the grating (814,914)and makes them parallel. The transform optic 1008 then spatiallyoverlaps all the chief rays onto the grating 1014. As such there is onlyone combined output beam 1025 a along this dimension. Along thenon-dispersion axis 1000 b a single lens chief ray collimator 1006 isall that is needed for 905 b. A slightly modified system for 805 b wouldbe needed. Each of these optical elements are cylindrical optics.However, in practice, some cylindrical optics may be replaced/combinedto form a spherical optics.

Hybrid System

FIGS. 13A-B illustrate a hybrid version of a Wavelength Stabilizer andCombiner where optics for resonator and combiner are shared. Thetransform optic 1308 converts all the near field positions of emittedbeams 1303 a into angles along the dispersion dimension 1300 a. Thecombination of mirror 1330 and first grating 1314 stabilize the gainelements 1302 by sending feedback 1310 a to produce unique wavelengths.The wavelength combiner grating 1344 is placed at the position where allthe emitted beams are overlapped. Thus, a single output beam 1325 a isproduced along the dispersion/combing dimension 1300 a. Telecentricoptics 1306, along the non dispersion dimension 1300 b, direct images ofthe emitted beams 1303 b onto the mirror 1330 and combiner grating 1344.

The efficiency of the diffraction grating in most systems is oftendependent on the polarization of the laser. Using a wave plate, insertedbetween the grating and the source, is one way used to match thepolarization. This is particularly useful when diode bars or otherasymmetric beams are used as the emission source. As a result, by usingthis technique, about 90% of the light is diffracted into the firstorder and 10% is diffracted into the 0th order and wasted.Alternatively, without a wave plate about 10% of the light is diffractedinto the first order and the remaining goes into the zero order.

FIG. 14 illustrates another hybrid version wavelength combiner andstabilizer system. In hybrid wavelength stabilizer/combiner 1400, waveplate 1417 is positioned between grating 1414 and a second reflectivesurface 1431. Emitters 1402 emit a beam that is overlapped onto thediffraction grating 1414 by a transform optic 1408 where in someconfigurations approximately 90% of the light is diffracted into the 0thorder and transmitted towards second reflective surface 1431 while theremaining 10% is diffracted in the 1^(st) order and directed toward afirst reflective surface 1430. It should be noted that the amount oflight diffracted and transmitted through a grating may vary. Forexample, some gratings allow for 90% of the 1^(st) order to betransmitted through the grating (if polarization is aligned), othersallow up to 95% and even up to 99%. However, gratings with higherallowance percentages of light in a single order that is transmitted aredifficult and expensive to manufacture and buy.

Feedback 1410 from the first reflective surface 1430 is directed backonto diffraction grating 1414 where a majority (the 0^(th) order from1430 as the source) transmits as output 1425 as a combinedmulti-wavelength beam. Another portion small (the 1^(st) order from 1430as the source) is redirected back into emitters 1402 and used tostabilize the emitters with unique wavelengths based on the angle ofeach beam was directed onto grating 1414. Similar to other embodimentsdescribed herein telecentric optics 1406 are used along thenon-dispersive direction (not shown) to stabilize the emitters in thatdimension.

The original 90% of light 1405, transmitted from emitters 1402, into the0^(th) order towards second reflective surface 1431, is collimated withoptical element 1418. 1405 then passes through a quarter wave-plate 1417and is reflected back as feedback 1412 to grating 1414 by secondreflective surface 1431, where the beams are now polarized anotherquarter and become orthogonal to the original 0^(th) order (1405)directed toward 1431. Optical element 1418 now overlaps the returningbeam 1412 onto grating 1414 where a majority transmits as output 1425and a smaller polarized portion is directed back into emitters 1402.This polarized feedback does not influence the stabilization of emitters1402 and in some cases is of a negligible amount and becomes reabsorbedas heat in the system. Telecentric optics 1416 perform a similarfunction in the combiner portion of the system as 1406 in the stabilizeportion of the system both having power along the non-dispersivedimension. Thus, the output beam 1425 is a combination feedback 1410 and1410 that forms a multi-wavelength stabilized output. In this system thestabilizer/resonator portion is comprised of optical elements 1406,1408, 1414 and 1430, while the the combiner portion is comprised ofoptical elements 1414, 1416, 1417, 1418, and 1431, where 1414 is sharedbetween each portion.

As shown above and in other WBC architecture systems the 1^(st) order ofdispersed light from the grating is used to stabilize the emitters. FIG.15 shows a 3-lens, 1-D WBC resonator system 1500. As shown, in FIG. 15there are three sets of beams (1525, 1526, and 1527) dispersed fromgrating 1514. In this embodiment, there are two 0^(th) order (1526,1527) and one first order (1525) beams. The first order beam is theoutput beam 1525 and is the brightest. Transform optic 1508 overlapsemitted beams 1503 onto grating 1514 thereby producing three sets ofdiffracted beams 1525, 1526, and 1527. A partially reflective outputcoupler 1520 is used to redirect some of the 1^(st) order beam back intothe emitters 1502 and wavelength stabilize the system. An afocaltelescoping system 1506 a-b is used with an optional slit 1509 to helpreduce cross-talk. Beam dumps are generally needed for 1526 and 1527.

FIG. 16 illustrates a WBC architecture hybrid system that isfundamentally different from the previous embodiments wherein instead ofusing the first order beam (1625) to wavelength stabilize emitters 1602the 0^(th) order beam 1627, which is reflected by first mirror 1631 asfeedback 1612 is used. By using the 0^(th) order to stabilize theemitters 1602 in this new implementation a number of limitationsassociated with a 1^(st) order cavity are overcome. These limitationsare: higher efficiency cavity, easier to align optics at high power, andeasier to design beam shaping optics. 1600 may be modified and apply toall WBC cavities (1-D and 2-D WBC of 1-D and 2-D laser/amplifierelements).

Contrasting 1600 with 1500 shown in FIG. 15, embodiment 1600 comprises afirst transform lens/afocal telescope 1608, diffraction grating 1614, asecond transform lens/afocal telescope 1618, a first mirror 1631,expanding optical elements/system 1606 a-b, optional slit 1609, andsecond mirror 1630. The output beam 1625 is taken from the 1^(st)diffraction order of the grating 1614. All the emitted beams 1603 areoverlapped onto the diffraction grating 1614 by first transform lens1608. The 0^(th) order 1627 beam (shown as transmitting through thegrating) is intercepted by 1618. 1608 and 1618 form an afocal telescopesystem. The emitters 1602 are at the focal plane of 1608 and the firstmirror 1631 is at the focal plane of 1618. The separation between thetwo lenses (1608, 1618) is the sum of their respective focal lengths.Thus, as such, real images of the emitters 1602 are formed at the firstmirror 1631.

When the images are reflected off the first mirror 1631 as feedback 1612they pass through 1618 a second time. Now 1618 functions as a transformlens for feedback 1612 (the real images of the elements) and overlapsthe beams onto the diffraction grating 1614. A portion of feedback 1612is now redirected into emitters 1602 as wavelength stabilized feedback,while another portion is directed towards second mirror 1630, oropposite in angle to the 1^(st) order diffracted beam 1603. Anexpanding/contracting optical system 1606 a-b is used to reducecross-talk and may be used with an optional slit 1609. The ratio offocal lengths between optical elements 1606 a:1606 b may be in the rangeof 1:10, 1:25, or 1:100. 1626 is reflected by second mirror 1630 asfeedback 1610 where a majority is redirected towards first mirror 1631and a portion transmits on as output 1625, which is comprised oftransmitted 1610 and the 1^(st) order of diffracted light of 1603. Oneof the advantages of this type of system are a majority of the lightgets re-circulated and utilized, while no beam dumps are required.

In many of the embodiments described herein a two-dimensional array ofradiation elements or emitters are stabilized along the non-dispersivedirection through use of a telecentric optical system, while a secondtelecentric optical system is used in the wavelength beam combiner sideof the multi-beam high brightness output laser system. Along thedispersive dimension and combining dimensions embodiments have beendiscussed herein using single dispersive element such as a diffractiongrating to 1) assist in stabilizing unique wavelengths along thedispersion direction and another dispersive element along the beamcombining dimension to 2) overlap each of the unique beams into a singlemulti-beam output profile. However, as discussed and shown a systemusing a common dispersive element to 1) stabilize unique wavelengths and2) later combine the unique wavelengths in a second step (referred to asa hybrid system) along the same common dispersive element or gratingrequires only a single grating.

The above description is merely illustrative. Having thus describedseveral aspects of at least one embodiment of this invention includingthe preferred embodiments, it is to be appreciated that variousalterations, modifications, and improvements will readily occur to thoseskilled in the art. Such alterations, modifications, and improvementsare intended to be part of this disclosure, and are intended to bewithin the spirit and scope of the invention. Accordingly, the foregoingdescription and drawings are by way of example only.

What is claimed:
 1. A multi-beam stabilizer and combining systemcomprising: a wavelength stabilizer having a dispersive dimension and anon-dispersive dimension, the wavelength stabilizer comprising: an arrayof beam emitters each (i) having front and back facets and (ii) emittinga beam from the front facet, one or more first optical elements (i)having power along the dispersive dimension of the wavelength stabilizerand (ii) arranged to receive the emitted beams and parallelize chiefrays of the emitted beams, and a first dispersive element arranged toreceive the beams from the one or more first optical elements anddisperse the beams into at least two orders, wherein one of the ordersis reflected back to the array of beam emitters by a feedback element,thereby forming a resonator between the back facet of each beam emitterand the feedback element that stabilizes the beam emitted by each beamemitter to a unique wavelength; and a wavelength combiner having adispersive dimension and a non-dispersive dimension, the wavelengthcombiner comprising: one or more second optical elements, different fromthe one or more first optical elements, arranged to receive thewavelength-stabilized beams and cause the beams to converge along abeam-combining dimension, and a second dispersive element, differentfrom the first dispersive element, positioned along a beam-combiningdimension, to receive the plurality of converging beams, and transmitthe beams as a multi-wavelength output.
 2. The system of claim 1,wherein the first dispersive element comprises a grating, a chirpedgrating, a surface grating, a volume grating, a transmission grating, ora prism.
 3. The system of claim 1, wherein the one or more first opticalelements are telecentric.
 4. The system of claim 1, further comprisingcollimating optics for collimating the beams emitted by the array ofbeam emitters.
 5. The system of claim 1, wherein the array of beamemitters is one-dimensional or two-dimensional.
 6. The system of claim1, wherein the feedback element is the first dispersive element.
 7. Thesystem of claim 1, wherein the feedback element comprises a mirrorarranged to receive one of the orders from the first dispersive elementand reflect the received order back to the first dispersive element. 8.The system of claim 1, wherein the feedback element comprises (i) afirst mirror arranged to receive one of the orders from the firstdispersive element and reflect the received order back to the firstdispersive element, and (ii) a second mirror arranged to receive adifferent one of the orders from the first dispersive element andreflect the received order back to the first dispersive element.
 9. Thesystem of claim 8, wherein the feedback element comprises one or moreoptical elements for imaging the beams onto the first mirror and/or thesecond mirror.
 10. The system of claim 8, wherein the feedback elementcomprises one or more quarter wave plates.
 11. The system of claim 8,wherein the feedback element comprises one or more slits for reductionof cross-talk between emitters.
 12. The system of claim 1, furthercomprising one or more third optical elements (i) having power along thenon-dispersive dimension of the wavelength stabilizer and (ii) arrangedto receive one or more orders from the first dispersive element andimage the received one or more orders onto the feedback element.
 13. Thesystem of claim 1, further comprising one or more third optical elements(i) having power along the non-dispersive dimension of the wavelengthstabilizer and (ii) arranged to receive the wavelength-stabilized beamsand cause chief rays thereof to be parallel in the non-dispersivedimension of the wavelength stabilizer.
 14. The system of claim 1,further comprising a beam splitter for transmittingwavelength-stabilized beams to the wavelength combiner.
 15. The systemof claim 1, wherein the wavelength-stabilized beams are received by thewavelength combiner via the back facets of the beam emitters.
 16. Amulti-beam stabilizer and combining system comprising: a wavelengthstabilizer having a dispersive dimension and a non-dispersive dimension,the wavelength stabilizer comprising: an array of beam emitters each (i)having front and back facets and (ii) emitting a beam, one or more firstoptical elements (i) having power along the dispersive dimension of thewavelength stabilizer and (ii) arranged to receive the emitted beams andconverge chief rays of the emitted beams, and a first dispersive elementarranged to receive the beams from the one or more first opticalelements and disperse the beams into at least two orders, wherein one ofthe orders is reflected back to the array of beam emitters by a feedbackelement, thereby forming a resonator between the back facet of each beamemitter and the feedback element that stabilizes the beam emitted byeach beam emitter to a unique wavelength; and a wavelength combinerhaving a dispersive dimension and a non-dispersive dimension, thewavelength combiner comprising: a second dispersive element, differentfrom the first dispersive element, (i) having power along abeam-combining dimension, and (ii) arranged to receive thewavelength-stabilized beams and combine the beams into amulti-wavelength output.
 17. The system of claim 16, wherein thewavelength combiner comprises one or more second optical elements,different from the one or more first optical elements, arranged toreceive the wavelength-stabilized beams and cause the beams to convergeto the second dispersive element.
 18. The system of claim 16, wherein atleast one of the first or second dispersive elements comprises at leastone of a grating, a chirped grating, a surface grating, a volumegrating, a transmission grating, or a prism.
 19. The system of claim 16,further comprising collimating optics for collimating the beams emittedby the array of beam emitters.
 20. The system of claim 16, wherein thearray of beam emitters is one-dimensional or two-dimensional.
 21. Thesystem of claim 16, wherein the feedback element is the first dispersiveelement.
 22. The system of claim 16, wherein the feedback elementcomprises a mirror arranged to receive one of the orders from the firstdispersive element and reflect the received order back to the firstdispersive element.
 23. The system of claim 16, wherein the feedbackelement comprises (i) a first mirror arranged to receive one of theorders from the first dispersive element and reflect the received orderback to the first dispersive element, and (ii) a second mirror arrangedto receive a different one of the orders from the first dispersiveelement and reflect the received order back to the first dispersiveelement.
 24. The system of claim 23, wherein the feedback elementcomprises one or more optical elements for imaging the beams onto thefirst mirror and/or the second mirror.
 25. The system of claim 23,wherein the feedback element comprises one or more quarter wave plates.26. The system of claim 23, wherein the feedback element comprises oneor more slits for reduction of cross-talk between emitters.
 27. Thesystem of claim 16, further comprising one or more third opticalelements (i) having power along the non-dispersive dimension of thewavelength stabilizer and (ii) arranged to receive one or more ordersfrom the first dispersive element and image the received one or moreorders onto the feedback element.
 28. The system of claim 16, furthercomprising one or more third optical elements (i) having power along thenon-dispersive dimension of the wavelength stabilizer and (ii) arrangedto receive the wavelength-stabilized beams and cause chief rays thereofto be parallel in the non-dispersive dimension of the wavelengthstabilizer.
 29. The system of claim 16, further comprising a beamsplitter for transmitting wavelength-stabilized beams to the wavelengthcombiner.
 30. The system of claim 16, wherein the wavelength-stabilizedbeams are received by the wavelength combiner via the back facets of thebeam emitters.
 31. A method of stabilizing and combining an array ofemitters each emitting a beam, the method comprising: forming astabilizer cavity wherein each emitter forms a resonator with anexternal reflective surface to thereby stabilize the beam emitted byeach emitter to a unique wavelength, wherein each beam emitted by thearray of emitters is introduced to a first dispersive element disposedwithin the resonator; transmitting the beams of the stabilizer from thefirst dispersive element into a wavelength combiner comprising (i) atleast one combining optical element and (ii) a second dispersiveelement; and combining the beams along one dimension to form amulti-wavelength beam output that is transmitted away from the array ofemitters.
 32. The method of claim 31, wherein the first dispersiveelement comprises a grating, a chirped grating, a surface grating, avolume grating, a transmission grating, or a prism.
 33. The method ofclaim 31, wherein the second dispersive element comprises a grating, achirped grating, a surface grating, a volume grating, a transmissiongrating, or a prism.
 34. The method of claim 31, wherein the beams ofthe stabilizer are transmitted into the wavelength combiner through backfacets of the emitters.